The fresh air system is a system that provides indoor and outdoor air exchange to a closed indoor space.

The fresh air system is driven by a fan to introduce air with a relatively high oxygen content from the outside and exhaust air with a high carbon dioxide content in the room. If the newly renovated house has a high formaldehyde and TVOC content, these gaseous pollutants will also be discharged.

Usually, the fresh air system consists of four parts: an intake duct, an exhaust duct, two fans, and a heat exchanger. The intake duct is responsible for introducing outdoor air into the room, and the exhaust duct is responsible for discharging the indoor air out of the room, and the fan plays a driving role, that is, provides the power of the air flow. The heat exchanger can transfer the heat (winter) or cold (summer) contained in the discharged indoor air as much as possible into the air entering the room to avoid the wind temperature coming in summer is too high or the wind coming in winter is too cold.

It is not possible to replace the air conditioner, because the air conditioner is active heating and cooling, and the heat exchanger is passive heat recovery, which can only reduce energy loss as much as possible, and does not actively heat or cool.

For unrenovated houses, there are two types of installation methods: ceiling type and cabinet type. The ceiling machine installs the ceiling of the new fan main unit on the roof, and the air inlet and the air outlet are connected to the host through pipes in each room. The cabinet machine installs the main unit of the new fan in the room and connects it to the air inlet and outlet of each room through pipes. For the ceiling and cabinet machines, the designer can hide the host and the pipe through some aesthetic treatment.

For the renovated house, a wall-mounted machine can be installed separately in the bedroom, and the air volume is generally between 60 and 150 cubic meters per hour. The wall-mounted machine is generally small in size and has a small cross-sectional area of the filter screen, and is suitable for use in a room within 20 square meters. If the air volume is increased by increasing the power of the motor alone, there is a problem that the filter needs to be frequently replaced, and the noise increases as the filter time increases. The ceiling machine before the decoration is generally 150-500 cubic meters / hour, suitable for families of 80-200 square meters. The cabinet machine can be divided into two types: the pipe machine used before decoration and the direct-blowing machine used after decoration. The air volume is similar to that of the ceiling machine, generally between 150-500 cubic meters per hour. However, the same type of cabinet machine has a larger filter screen area and a larger heat exchanger volume, so the operation is quieter, the heat loss is less, and the frequency of replacing the filter is smaller.

Calculate according to the hourly air exchange rate of at least 1.2 times, or the per capita air volume of 30 cubic meters per hour. In addition, it is also related to the airtightness of the house. If the house is not well sealed, it will be bigger when choosing a model.

The installation is convenient. There are two holes on the back of the machine to connect with the outside, one is the air inlet pipe and the other is the exhaust pipe. If the wall is not convenient for punching, you can also punch holes in the glass. Air is blown from the front of the front of the machine and exhausted from the lower part of the side. There is no need to take the pipe in the room, which has less impact on the decoration effect.

The air intake and exhaust of most new wind turbines are designed according to 1:1. However, there are also new fans to adjust the amount of exhaust air by adjusting the power of the exhaust motor. When the return air ratio is 1.2, it can be understood as a strong row mode, which is suitable when the indoor air is worse than the outside. For example, there is a house inside. The taste of cooking, etc.; when the return air ratio is 1.0, the exhaust air is slightly larger than the intake air, which is suitable for outdoor pollution, and the temperature is better than the indoor; when the return air ratio is 0.8, the air intake ratio is The exhaust air is slightly larger, suitable for the outside air is not very bad, this mode has the least impact on temperature; when the return air ratio is 0.6, the air intake is larger than the exhaust air, and the indoor can form a slight positive pressure to resist the external pollution. Air enters the room through the gap of the house, which is suitable for the outside air, which has a negative impact on heat recovery.

Factors affecting the effectiveness of new wind turbines have both external and internal factors. The external cause is mainly the type and concentration of outdoor pollutants. For the Beijing area, the external pollutants are mainly PM2.5 solid particles. For small and medium-sized cities, in addition to PM2.5, there is also the smoke smell of coal burning by residents, that is, gaseous pollutants. The internal cause mainly refers to the PM2.5 and some smoke smells formed by the cooking in the kitchen, and the environmental pollution caused by smoking at home. If an ultrasonic humidifier is used, the use of ordinary tap water will cause the concentration of PM2.5 to increase after the calcification in the droplets is precipitated in the air. The other is the tightness of the house, the better the tightness of the house, the better the effect of the fresh air system.

By controlling the operating mode of the new fan, that is, the positive pressure mode, when the return air ratio is set to 0.6, the air in each room can be purified. If the house is well sealed, when the concentration of PM2.5 in the outdoor air is around 200, the concentration of PM2.5 in the living room and bedroom can generally be below 20; when the concentration of PM2.5 in the outdoor is around 300. It is also possible to achieve a standard of 35 or less in the room, that is, an excellent standard; if the outdoor PM2.5 concentration is around 500, a house with a general tightness can also achieve a standard of 75, which is a good standard.

The impact is very big! For example: a house of about 120 square meters in three rooms and two halls, and a direct blower type new fan with a volume of 350 cubic meters. If all the doors and windows are closed, when the concentration of outdoor PM2.5 is around 450 (measured), the living room is about 25, and the room is about 35~40. But when the kitchen window is opened halfway, even if the kitchen door is closed (the lower part has a gap of about 1 cm), the PM2.5 concentration in the kitchen is basically the same as the outdoor, and the PM2.5 concentration in the living room will reach 80~100. about. Seriously affect the quality of indoor air.

The new fan can continuously introduce fresh air into the room, and discharge the indoor carbon dioxide and high formaldehyde concentration air, so that the indoor formaldehyde, even the new house, can be kept at a low level, that is, it will be discharged when it is volatilized.

The portable formaldehyde detector measures the aldehyde group, but it cannot distinguish the aldehyde-containing components in formaldehyde, ethanol, perfume, and shower gel. If you drink alcohol while eating at home, or if there are other flavors, the detector will explode. But this time the monitoring is an illusion, not a real explosion of formaldehyde. If you need to discharge this smelly gas as soon as possible, you can open the return air ratio.